spindlecell

Spindle cell is a descriptive term used in histology and pathology to denote a cell with an elongated, slender, fusiform shape that tapers at both ends. It is a morphological description rather than a specific cell lineage, and several different cell types can appear spindle-shaped.

In normal tissue, spindle-shaped cells arise from mesenchymal lineages. Examples include fibroblasts, myofibroblasts, and smooth muscle cells, as well as Schwann cells in the peripheral nervous system. These cells commonly organize into parallel bundles or fascicles and contribute to tissue structure, connective tissue production, and contractile functions.

In pathology, many tumors are described as spindle cell tumors because they are composed predominantly of spindle-shaped cells. These tumors can be benign (such as fibromas, schwannomas, and leiomyomas) or malignant (such as fibrosarcomas, leiomyosarcomas, and malignant peripheral nerve sheath tumors). The diagnosis often depends on architectural patterns (for example, fascicular, storiform, or herringbone arrangements) and immunohistochemical profiles that help identify the presumed lineage. Common markers include vimentin (a general mesenchymal marker), desmin and smooth muscle actin for myogenic differentiation, S-100 for neural crest–derived tumors, and cytokeratins for epithelial-derived spindle cell carcinomas. The spindle cell appearance can overlap across different tumor types, so a panel of markers and correlation with clinical and radiologic data are typically required to establish a precise diagnosis.

Overall, spindle cell morphology is a key descriptive feature in both normal histology and a broad range of benign and malignant neoplasms.